In 2001 Caterpillar introduced 365B Series II in Belgium, with a DER serial number prefix. Cat released four more new units by 2004. They all come standard with 443 horsepower (HP).

The new units were manufactured in Belgium, with a PEG, JMB, or SDL prefix; and in Japan, with a BTH prefix.

The JMB, DER, and BTH units have linkage specs for a long boom and medium stick. The DER unit has an operating weight of 146,960 pounds (66,800 kg). The JMB unit has an operating weight of 144,540 lbs (65,700 kg). The BTH unit has an operating weight of 143,660 (65,300 kg).

The PEG unit has a max reach at ground level of 31 feet (9.5 m) and a max digging depth of 10 ft (3 m). It has an operating weight of 156,200 lbs (71,000 kg).

The DER is a material handler unit with a square based frame. It has an operating weight of 160,600 lbs (73,000 kg).

Based on data from the sales database of Ritchie Bros. Auctioneers, it is estimated that more than 1,500 Caterpillar 365B/365B Series II hydraulic excavators/material handlers have been produced.